Workplace accomodations

I’m 29 weeks with a job that requires me to be in office 3x a week. Because of the borderline hostile work environment from management towards the staff, I’ve been physically and mentally drained to keep showing up at this rate. Thankfully, I have a low risk pregnancy but this also makes it seem like it’s ok for my employers to keep asking me of things such as helping to do some light physical labor around the office. In fact, it feels like I didn’t have a choice to say no and was expected to help out from one of the managers. At this point, protecting my peace and my baby is my biggest priority and I’ve been looking into requesting accommodations such as no lifting or increased WFH if possible. I don’t plan on discussing the work environment with my direct manager as that is a bigger issue beyond me (they’re also jaded) but id like to give them a heads up of my physical limitations before I show up with a medical note as a courtesy that it’s coming. How do I simply state to them that I have limitations that they may not be aware about (and legally can’t disclose) but i will be working with my doctor’s for some accommodations? Or how would you word it?